1. Field of Invention
The invention relates to a blower, and in particular to a blower having a plurality of impellers.
2. Related Art
Conventionally, blowers are classified into single side entry blowers and double side entry blowers. Referring to FIG. 1 and FIG. 2, FIG. 1 is a schematic illustration showing a conventional single side entry blower having a single impeller, and FIG. 2 is a cross-sectional view taken along the line A-A′ in FIG. 1. In FIG. 1 and FIG. 2, a blower 1 includes a housing 11 and an impeller 12. The housing 11 has a top cover 111, a bottom cover 112 and an air outlet 113. The top cover 111 has an opening to serve as the air inlet 114 of the blower 1. When the impeller 12 rotates, the blades 121 of the impeller 12 forces the airflow by sucking air outside through the air inlet 114 and blowing out the air through the air outlet 113 of the housing 11.
In order to prevent the heat dissipation from stopping since the single blower breaks down, two blowers may be combined together. FIG. 3 is a schematic illustration showing a conventional combined blower having two blowers. FIG. 4 is a cross-sectional view taken along the line B-B′ in FIG. 3. Referring to FIGS. 3 and 4, a combined blower 2 has a first blower 21 and a second blower 22. The first blower 21 and the second blower 22 respectively have air inlets 211 and 221 and air outlets 212 and 222. The air outlet 212 of the first blower 21 extends via a hollow housing 213 and is disposed with the air outlet 222 of the second blower 22 side by side, and the second blower 22 is stacked on the hollow housing 213.
The first blower 21 and the second blower 22 force the air to enter the first blower 21 and the second blower 22 through the air inlets 211 and 221, and then the airflows enter the respective air passage of first blower 21 and the second blower 22. Then, the airflows are blown out through the air outlets 212 and 222, respectively. That is the first blower 21 and the second blower 22 are two independent apparatuses. As the results, a larger space is needed to accommodate the two blowers. Also, an additional material, such as the hollow housing 213, is needed to assemble the two blowers. Therefore, the material cost is increased, but the airflow performance of the combined blower 2 is not enhanced comparing to two single blowers.
Thus, it is an important subject of the invention to provide a combined blower capable of integrating a plurality of blowers without wasting the material cost and enhancing airflow performance.